If 1/2 of 1 is 1/2 what is 1/2 of 2 3 and 4?

An office supply company conducted a survey before marketing a new paper shredder designed for home use. in the survey, 80 % of the people who tried the shredder were satisfied with it. because of this high satisfaction rate, the company decided to market the new shredder. assume that 80 % of all people are satisfied with this shredder. during a certain month, 100 customers bought this shredder. find the probability that of these 100 customers, the number who are satisfied is 69 or fewer.

Plz hurry evaluate the expression a+b where a=8 and b=19

If each bricks costs and he can only buy one brick how much will it cost him to get the material to put around the outside of his garden?